Generic protective pipe arrangements including slitted corrugated pipes for the automotive field are known, for example, from EP 0 268 869 B1. WO 97/32379 discloses a protective pipe which is provided with a slit that is inwardly covered by an overlapping portion. This type of protective pipe for electrical cables has the disadvantage that a strong stiffening of the pipe along the slit and overlap regions results so that, when the pipe is installed, for example, in a bent condition in the engine compartment of a motor vehicle, it gapes apart and exposes the electrical cables to be protected to the environment. Furthermore, it is problematic with this arrangement to guide electrical conductors out of this protective pipe through the slit, since the covering portion for the slit exerts localized stress on the electrical conductors and leads, especially together with the effect of large temperature variations and the vibrations in the engine compartment to the conducting cores of the electrical cables being exposed, which is especially problematic in modern vehicles, since here electrical and electronical control conductors can be used which are responsible for a reliable operation of the vehicle. It is furthermore extremely cumbersome to manufacture this type of pipe, since the covering region must be manufactured together with the pipe in a closed shape and, subsequently, sawed through from one side in order to open the slit. Subsequently, the pipe must again be strongly heated and the pipe must be pressed together in the heated, at least partially softened condition in order to close the slit so that the overlapping region can carry out its covering function. This type of manufacture is time consuming and costly, and the result can in no way justify the cost. Because of the overlap, the cables are very hard to insert or only with a specialized tool.
A pipe with axial slit is known from DE 196 24 984 A1 wherein the slit has a longitudinal extent which deviates from a straight line. An ondulated line is here considered practical. However, deformations occur which are caused by the ondulated line in the pipe. It is also extremely difficult with this type of pipe arrangement to provide a slit which deviates from a straight line. Special tools must be used herefor which furthermore operate relatively slowly. The manufacturing costs are also not justified by the results and the cables are hard to insert and only with an auxiliary tool because of the overlap.
A wrapping channel for the wrapping of cable bundles is known from EP 0 750 378 A1 which is slitted in its longitudinal direction whereby a costly closure mechanism is formed along the slit. A stiffening of the protective pipe over its whole length is here also present, which is unacceptable.
EP 0 114 213 A2 discloses a protective pipe with a complicated hook-shaped closure. DE 44 10 706 A1 also discloses a pipe, especially a corrugated tube which is provided with costly closure mechanisms.
The generic prior art discloses a protective pipe arrangement for conduits and especially for electrical conductors, whereby two slitted corrugated pipes are inserted one into the other so that the inner or outer protective pipe covers the slit in the other protective pipe. This type of protective pipe arrangement is very advantageous with respect to protection for the electrical conduits, whereby deformations of this protective pipe arrangement along the slit are also prevented so that a squeezing of or an undesired insulation removal from the electrical cables is not possible, but this type of protective pipe arrangement requires a comparatively high amount of plastics material during manufacture and requires, especially with small pipe dimensions, a large force to install or uninstall the protective pipe arrangement. The very high installation cost also dampens the acceptance of this otherwise good concept.